In our 2nd letter to the Kleins/ Salt Company, we asked about the possibility of putting a trailer (here “caravan”) at our camping spot near the oyster hatchery. As the weather has grown cooler and damper, we have moved increasingly into the hatchery, especially for meals and, sigh, long stints on our computers. The hatchery is certainly warmer – a combination of wind protection and heated water – but also humid and a little cramped due to tanks, filters, raceways, and odds and ends of production and research equipment. Since April 6, the tanks have been full of Ostrea edulis larvae: one of the oysters that Alan collected from the salt pond must have been brooding, and he has since been father to 10s of thousands – feeding them microalgae from the guano pond, adjusting their temperature, and changing their water regularly. But the hatchery is not really a place to hang out during the winter. The Kleins were happy to allow some more permanent camping structures, so we started looking at a variety of options: The few used trailers that Alan priced were around $N70,000, out of our range. We were excited for a while about products offered by the Container Company, which provides shipping containers for all sorts of purposes, complete with doors and windows if you wish. But they too were a bit expensive. Meanwhile, the Kleins were also looking around for housing options, and they have been much more successful! First, they found a contractor to build a 5x4 m room on one side of the hatchery – as an extreme example of how cheap some materials and labor are, the entire concrete block building cost $N7000. About 7 people worked on it for nearly a week. Okay, so it’s not exactly square, and mortar was used generously to get the window and door to fit…. The Kleins have outfitted it with spare parts from their properties – a bay window with a bay view, work table and sink, and desk. It will be a fantastic place to use microscopes (less rusty than the hatchery sauna), work on papers, and watch the winter weather on the coast, while keeping an eye on any larvae that we can foster overwinter. So – there is now a new marine lab with running seawater on the Namibian coast, just meters away from some exceptional rocky intertidal areas, close to the salt ponds and bird sanctuary! We can easily see that there is a lifetime of questions to be answered here.
The Kleins also rescued a vintage 70s caravan from a neighbor’s backyard, painted the outside, cleaned the spiders out of the inside, and have provided us with a dining and living room. It’s about 2x3 m. The windows at each end prop open, and a bit of the top pops up, which allows Alan to look outside (and stand up straight!). The 2-burner stove seems heavenly after cooking on the Bluet (hunched over one burner), as does sitting at a table to eat. I guess after a month and a half and a little cold wind, camping has lost some of its luster. Katie has already fallen in love with the caravan (dubbed Hotel California by the Kleins), literally crying when it was hauled away to a safer storage place while we were in Windhoek. We owe the Kleins for many things – stimulating conversations, access to field sites, several fresh fish to grill on the braai (=barbecue in Namibia), the key to the hot shower near the Seabird Guano (Pty) building, and now these truly generous acts to help us be comfortable and productive. Well, the only drawback to the new lab is that it is possible to get locked inside the hatchery – this happened one night when I went back in to work on curriculum documents. I kept thinking that Alan would come rescue me as soon as Katie awoke and needed her mom to get back to sleep, which always happens by 10 pm… or at least by midnight… although sometimes she can sleep through until 2 am… and apparently Alan can pat her back to sleep until 3:30 am, when he at last opened the door and wondered when I was coming to bed. I was only too glad to do so.
So there it is: Panther Bake Marine Lab. Panther Bake should be pronounced in German, and Panther was the name of the German ship that placed a light (bake) at that site many decades ago. The light is now gone, but the name remains to grace the salt “mining” area and other activities on that stretch of coast.
Showing posts with label Coast. Show all posts
Showing posts with label Coast. Show all posts
Friday, May 2, 2008
Tuesday, March 25, 2008
Sulfide eruption!
The past three weeks have been devastating for the oyster growers on Namibia’s coast at Walvis Bay. A large phytoplankton bloom, which turned the water into a thick chocolate of spiky dinoflagellates, was followed by a sulfide eruption, when the toxic gas that accumulates in the sediment as a by-product of anaerobic decomposition bubbled up. Hydrogen sulfide is itself toxic, and it reacts with oxygen in seawater, causing hypoxia. The color of the water turns an almost tropical aquamarine, but accompanied by the stench of rotting eggs. Close on the heels of this sulfide eruption came another phytoplankton bloom. Growers are reporting losses of literally millions of oysters, from 25% to more than 70% of their crops. They have little buffer for these losses, since many of the companies are just 2 or 3 years old, and people were counting on the next harvest to pay off debts from start-up costs. Some companies will probably fold altogether.
Oysters are not the only organisms that suffered from the toxic environmental conditions of the past few weeks. From 3/9 to 3/11 we visited rocky intertidal sites around Swakopmund during reasonably good low tides. Initially, we were so excited by what we saw: spiny lobsters, hundreds of them, wiggling their antennae from under any available intertidal ledge, or just hiding in the algae. “Wow”, I thought, “I’ve never seen so many intertidal predators in one place. This must be what it’s like to visit a “pristine” beach!” To the contrary: The lobsters had gathered there in hordes to escape the low-oxygen conditions of deeper water. And the beaches were hardly pristine, as people descended from above to strip as many of the easily-accessible lobsters as they were able to fit into mesh bags, lunch boxes, or plastic shopping bags. We saw some seasoned lobster-hunters in wet suits and gloves, but also some unusual suspects – businessmen in collar shirts and loafers, squabbling couples – all taking advantage of the coincidence of low tides and low oxygen. All sorts of regulations were violated – including catch limits (people would collect some, then stand in a parking lot to sell what they’d collected, then collect more) and size limits (lobsters are not supposed to be kept below 65 mm carapace length, but few people were bothering to measure, justifying that these lobsters were going to die anyway). Any rock small enough to be lifted had been overturned and not turned back. Solitary antennae washed back and forth in the waves and accumulated in the wrack on the beach, as people latched on to the most obvious, but frail, parts of the lobsters to catch them. Watching the interaction between people and these beautiful, vulnerable, probably keystone creatures sickened me.
Meanwhile, many other organisms were also suffering, but primarily from the environmental conditions, not from humans. Mobile species tended to move into the intertidal zone, notably small sharks and large octopus. Sessile species often succumbed: the first to go were the soft-bodied “red bait” (large Pyura ascidians), which I initially thought were horse dung on the beach; many of the lower mussels also died, and then dragged their epiphytes on shore, including kelp and bryozoans. On the oyster longlines in Walvis Bay, epiphytic hydroids had died and discolored, but interestingly the newly-settled native clams were still alive amongst the hydroid strands, even if just a few mm long. On the beach south of Swakopmund, it was clear that many fish had also been unable to escape the low-oxygen conditions: species included the serpent eel (pencil thin and more than a foot long with a beaky snout), clingfish known as rocksuckers, and many more that we didn’t take the time to identify. Death and devastation, the beach littered with bodies – we had never seen such a tangle of the ocean’s denizens cast up on shore like this.
This year’s environmental conditions have been strange. Of course, we have no grounds for personal comparison, but we read the newspapers and we ask around. Even though the inland rains started late (late January rather than November), they have been torrential: reservoirs are overflowing, rivers are flooding, and agricultural land and human infrastructure are under water. The ocean has been warmer than normal for 4 months, with temperatures well above 20C, compared to rare excursions above 18C in most years. Based on reading ahead of time, we expected strong and persistent southwest winds on the coast, but we have only experienced a scattered few days of these winds, with the more common pattern to be W or NW or simply weak winds. We do not know – in fact, no one knows, although there are many hypotheses – any clear relationship between this year’s weather and the devastation for coastal organisms. However, 2006 and 2008 were high-rain years for Namibia and also brought large sulfide eruptions. The weather patterns that bring rain could also trigger sulfide (directly from freshwater inflow to the coast, or from some joint meteorological conditions). We do know that the unusually warm ocean temperatures stem from the lack of upwelling, because little deep cold water comes to the surface, and the warm Angola current pushes south. Earlier this year, these warm water conditions were also associated with oyster mortalities, even before the blooms and eruptions. We also know that the winds determine the severity of sulfide eruptions in Walvis Bay, and the absence of SW winds to push the water offshore allowed phytoplankton or sulfide to accumulate within the bay.
Today, we participated in an emergency meeting of the oyster growers to discuss combined responses to their losses. This was an opportunity to collate information about the spatial and temporal patterns of mortality. Did oysters die in response to toxic phytoplankton, Vibrio bacteria after the phytoplankton crashed, or due to sulfide and low oxygen? (Unfortunately, this seems impossible to resolve because so many environmental changes happened simultaneously, and oysters can buffer themselves somewhat by closing up for a while.) Were oysters closer to the ocean/ mouth of Walvis Bay buffered from mortality because they received some clean water advected with tides? (From what we have heard, this appears to be the case.) Did oysters deeper in the water suffer higher mortality? (This also seems to be the case, consistent with a decline in oxygen concentration from the surface to depth.) We heard that oysters suffered higher mortality if recently cleaned of fouling organisms, and we suspect that this is because cleaning these fast-growing subtidal oysters chips their shells, so they cannot protect themselves by closing up against poor environmental conditions. So what could be done to toughen them up? Did the native clams survive as epibionts on the baskets throughout the bay, and if so, why not cultivate them? (They taste fine steamed in butter and garlic; personal observation).
The oysters growing onshore in the salt ponds at Walvis Bay and Swakopmund have weathered the recent ocean conditions with little trouble, except perhaps mortality of oyster larvae in the hatchery associated with the initial phytoplankton bloom. Because ocean water is pumped vigorously up into the salt ponds, it is well aerated by the time it reaches the oysters.
This has been an awful, but awesome event to witness as an ecologist – as a farmer, it would just be awful. I wonder if living in Africa for a year is a bit like having a terminal illness. Each seasonal event, each visited scene will never be experienced again.
Oysters are not the only organisms that suffered from the toxic environmental conditions of the past few weeks. From 3/9 to 3/11 we visited rocky intertidal sites around Swakopmund during reasonably good low tides. Initially, we were so excited by what we saw: spiny lobsters, hundreds of them, wiggling their antennae from under any available intertidal ledge, or just hiding in the algae. “Wow”, I thought, “I’ve never seen so many intertidal predators in one place. This must be what it’s like to visit a “pristine” beach!” To the contrary: The lobsters had gathered there in hordes to escape the low-oxygen conditions of deeper water. And the beaches were hardly pristine, as people descended from above to strip as many of the easily-accessible lobsters as they were able to fit into mesh bags, lunch boxes, or plastic shopping bags. We saw some seasoned lobster-hunters in wet suits and gloves, but also some unusual suspects – businessmen in collar shirts and loafers, squabbling couples – all taking advantage of the coincidence of low tides and low oxygen. All sorts of regulations were violated – including catch limits (people would collect some, then stand in a parking lot to sell what they’d collected, then collect more) and size limits (lobsters are not supposed to be kept below 65 mm carapace length, but few people were bothering to measure, justifying that these lobsters were going to die anyway). Any rock small enough to be lifted had been overturned and not turned back. Solitary antennae washed back and forth in the waves and accumulated in the wrack on the beach, as people latched on to the most obvious, but frail, parts of the lobsters to catch them. Watching the interaction between people and these beautiful, vulnerable, probably keystone creatures sickened me.
Meanwhile, many other organisms were also suffering, but primarily from the environmental conditions, not from humans. Mobile species tended to move into the intertidal zone, notably small sharks and large octopus. Sessile species often succumbed: the first to go were the soft-bodied “red bait” (large Pyura ascidians), which I initially thought were horse dung on the beach; many of the lower mussels also died, and then dragged their epiphytes on shore, including kelp and bryozoans. On the oyster longlines in Walvis Bay, epiphytic hydroids had died and discolored, but interestingly the newly-settled native clams were still alive amongst the hydroid strands, even if just a few mm long. On the beach south of Swakopmund, it was clear that many fish had also been unable to escape the low-oxygen conditions: species included the serpent eel (pencil thin and more than a foot long with a beaky snout), clingfish known as rocksuckers, and many more that we didn’t take the time to identify. Death and devastation, the beach littered with bodies – we had never seen such a tangle of the ocean’s denizens cast up on shore like this.
This year’s environmental conditions have been strange. Of course, we have no grounds for personal comparison, but we read the newspapers and we ask around. Even though the inland rains started late (late January rather than November), they have been torrential: reservoirs are overflowing, rivers are flooding, and agricultural land and human infrastructure are under water. The ocean has been warmer than normal for 4 months, with temperatures well above 20C, compared to rare excursions above 18C in most years. Based on reading ahead of time, we expected strong and persistent southwest winds on the coast, but we have only experienced a scattered few days of these winds, with the more common pattern to be W or NW or simply weak winds. We do not know – in fact, no one knows, although there are many hypotheses – any clear relationship between this year’s weather and the devastation for coastal organisms. However, 2006 and 2008 were high-rain years for Namibia and also brought large sulfide eruptions. The weather patterns that bring rain could also trigger sulfide (directly from freshwater inflow to the coast, or from some joint meteorological conditions). We do know that the unusually warm ocean temperatures stem from the lack of upwelling, because little deep cold water comes to the surface, and the warm Angola current pushes south. Earlier this year, these warm water conditions were also associated with oyster mortalities, even before the blooms and eruptions. We also know that the winds determine the severity of sulfide eruptions in Walvis Bay, and the absence of SW winds to push the water offshore allowed phytoplankton or sulfide to accumulate within the bay.
Today, we participated in an emergency meeting of the oyster growers to discuss combined responses to their losses. This was an opportunity to collate information about the spatial and temporal patterns of mortality. Did oysters die in response to toxic phytoplankton, Vibrio bacteria after the phytoplankton crashed, or due to sulfide and low oxygen? (Unfortunately, this seems impossible to resolve because so many environmental changes happened simultaneously, and oysters can buffer themselves somewhat by closing up for a while.) Were oysters closer to the ocean/ mouth of Walvis Bay buffered from mortality because they received some clean water advected with tides? (From what we have heard, this appears to be the case.) Did oysters deeper in the water suffer higher mortality? (This also seems to be the case, consistent with a decline in oxygen concentration from the surface to depth.) We heard that oysters suffered higher mortality if recently cleaned of fouling organisms, and we suspect that this is because cleaning these fast-growing subtidal oysters chips their shells, so they cannot protect themselves by closing up against poor environmental conditions. So what could be done to toughen them up? Did the native clams survive as epibionts on the baskets throughout the bay, and if so, why not cultivate them? (They taste fine steamed in butter and garlic; personal observation).
The oysters growing onshore in the salt ponds at Walvis Bay and Swakopmund have weathered the recent ocean conditions with little trouble, except perhaps mortality of oyster larvae in the hatchery associated with the initial phytoplankton bloom. Because ocean water is pumped vigorously up into the salt ponds, it is well aerated by the time it reaches the oysters.
This has been an awful, but awesome event to witness as an ecologist – as a farmer, it would just be awful. I wonder if living in Africa for a year is a bit like having a terminal illness. Each seasonal event, each visited scene will never be experienced again.
Monday, March 10, 2008
Month 3.1 trip to coast
2/27-3/7 2008
We’re spending a lot of time with Mother Goose and Dr. Seuss these days, consequently primed with rhymes for many occasions. For those of you who haven’t read “If I ran the zoo” recently, I’ll remind you that young Gerald McGrew imagines a whole lot of improbable and wondrous animals to populate his zoo: 10-footed lions, elephant-cats, the world’s largest bird called the Fizza-ma-Wizza-ma-Dill, Joats, Gootches, Palooskis, Nerkles, even Nerds, and the “bustard, who only eats custard with sauce made of mustard.” But there really are bustards… and now we’ve seen them! The largest species, the kori bustard, could reach the back of an ostrich (and lives in much the same open semi-arid habitat), has a dandy crest, and can fly at the speed of an underpowered combi (VW van) (pers. obs.). We’re not sure if it eats mustard or custard. Some other amazing birds we feel lucky to have seen: hornbills, korhaans (2 species so far, just slightly smaller than bustards, also long-legged desert denizens), vultures, pied (black and white) hawks, and of course flamingos, hundreds of them every day at our study site. Did you know that flamingos have voices similar to geese?
On this trip to the coast, we again took the tar road until the dirt cut-off to Henties Bay that skirts the Spitzkoppe. Two months ago, I wouldn’t have thought it possible that a “desert” landscape could look so lush – it seems to continue to green with summer rains. The “ah-ha” moment was seeing the patches of ground along the road that had appeared as desolate as “war zones” in January: bushes and small trees had been mercilessly uprooted and piled together sort of like slash, leaving just bare dirt behind. But now, these clearings are knee-high in grasses and forbs, gently waving in the wind. There is a sweet smell in the air. And one grass is particularly beautiful, with silvery seed heads nodding.
Even eastern areas of the Namib desert, areas previously seen with tufts of brown grass, now show green. The cows are beginning to lose their angular, ribbed appearance; goats are filling out; and grazing donkeys seem very happy. Just a note about donkeys: It’s taken us a while to realize that donkey carts remain an important means of transportation, particularly in rural areas. Teams of 2, 3, or 4 (sometimes combined with horses) can be seen traveling on dirt roads or along the margins of the tar roads in parallel tracks. Some of the donkeys look a little raw, underfed, and overworked. But they definitely are powered by renewable energy!
Into the western Namib, however, the dominant color is sandy beige-red-brown. Although we have personally witnessed 3 precipitation events on the coast this year, it is still not enough (rain, soil, seed bank?) to make obvious changes. Much of the vegetation consists of sparsely-spaced dark clumps of sand-holding plants. I always initially see these shapes as potential animals! But the animals of the desert look like sand and shimmering heat and are cryptic until startled and in motion.
There has been fantastic weather to observe from afar while camping on the beach near The Salt Company: Semicircular double rainbows, from rain caught by the setting sun. Just past dark, the lightning begins inland, so far away that we rarely hear thunder, sometimes lighting up a sheet of rain, or billowing clouds, or just streaking down to the ground. This is a perfect storm for Katie, who enjoys the fireworks but is troubled by the rumble of thunder.
We had only one uncomfortable night camping this time: the night was still and hot, like a steamer inside the Combi. In the absence of an ocean breeze, flies of all shapes and sizes and speeds gathered on our food and found their way into our sleeping area. When a bit of wind did blow, it was from the east, putting us downwind of the guano platform and directly in the path of the scent of 10s of 1000s of cormorants. We now call this platform the “stinky bird place”, although the proprietor says you get used to it: it’s the scent of money. In the middle of the night, Alan opened the sliding door on the side of the van and spent two hours on the alert, occasionally flashing the headlamp into the eyes of circling hyenas. (Okay, they probably weren’t really circling. That was just for African effect. They were hanging out at the fence line, although we know from their tracks that they do sometimes pass within a few meters of the Combi at night.)
Over the weekend, we did a self-guided tour of all the salt ponds, ranging in salinity from seawater to salt. From those with any life in them, we collected algal and water samples. For those of you with some marine training, we can report finding Dunaliella, ciliates, rotifers, ostracods, Ulva (was Enteromorpha), and a monoseriate, branched green alga, possibly Cladophora. For those of you who read any comics as kids, you’ll be happy to know that we found sea monkeys in the wild: brine shrimp by the millions!
With a month of sampling and thinking about the salt ponds, we finally felt ready to write down observations and questions for the Kleins. That document initiated a 3-hour conversation and confirmed that we can do a variety of experiments in the oyster pond, camp near their hatchery, and use their amazing workshop, which is an enormous room filled with Swedish machinery, much of which was unrecognizable to JR, but AT says they could basically build a motor from scratch in there. We used their drill press to drill tiles and watched them build a clam rake to Alan’s specifications. They do a lot of their own machinery repair, plus make such things as stainless steel nails (the correct 316 type for the guano platform can’t be acquired locally). With access to this workshop and the first “real” hardware store we’ve found, we feel like we’ve almost made up for the absence of Jack’s Country Store at Willapa Bay.
Hooray! We set up our first research project, which will compare growth and resources used by oysters transplanted near the “ocean” and throughout 2 salt ponds. Here, we wonder how much nitrogen in the salt pond comes from birds vs. ocean. This is similar to work in Willapa, except at a much smaller spatial scale (30 ha pond). We epoxied 2 oyster species to 15x15 cm tiles (this size tile is used everywhere in conjunction with concrete for building). To deploy them throughout the pond, we borrowed a “research vessel” – small rowboat (the motorized boat used by the oyster workers seems to have a lawnmower motor attached to a horizontal 1 m rod with a propeller on the end – the propeller is lowered just barely into the shallow water). Alan stood waist-deep in water and calf-deep in anoxic sediment of biodeposits and mica, then used a mallet and steel rod to pound a small hole in the hard gypsum layer. Slip out the rod, slip in a mahogany pole, cable tie the tile to the pole, and one sample is done: we set out about 35. Oysters (Ostrea edulis) spawned on Mar. 7, making a cloud of sperm in the water – just like in all the pictures we’ve seen.
Deploying the tiles took the whole day, so the sun was setting by the time we set up camp, and we ate curry-in-a-bag in the dark. We had a visitor: a gerbil, distinguished by the dark tip to its tail (and the fact that there are no coastal mice). We’d seen lots of tracks, but this was the first individual in the flesh. Common, but interesting daytime visitors are Camponotus ants, about a cm long with 2 bright orange spots on their black velvet abdomen. These apparently can spray formic acid when irritated, so we’ve tried not to irritate them! At least one beetle takes advantage of the ants’ nasty reputation by being the same size and color, complete with 2 bright orange spots to mimic.
On Tuesday, Mar 4 we attended a Namibian Mariculture Association meeting and had a fun time comparing the markets, methods, and magnitudes of oyster culture in Walvis and Willapa Bays. Bottom line: there are really teeny tiny operations here, but they are all looking for access to the high-end oyster market (4-Rand oysters, worth slightly more than 50 cents apiece). No one sells shucked meat; lots sell frozen in the shell (we’re dubious). The Namibian growers have been focusing on selecting fast-growing oysters, so it was good to be able to pass along a broad consensus that selection for survival is much more important. On our way from the meeting in Walvis Bay to our “campsite” in Swakopmund, we saw evidence of a sulfide eruption: tropically-blue water just along the shore. What does this bode for their oysters? Only time will tell.
We’re spending a lot of time with Mother Goose and Dr. Seuss these days, consequently primed with rhymes for many occasions. For those of you who haven’t read “If I ran the zoo” recently, I’ll remind you that young Gerald McGrew imagines a whole lot of improbable and wondrous animals to populate his zoo: 10-footed lions, elephant-cats, the world’s largest bird called the Fizza-ma-Wizza-ma-Dill, Joats, Gootches, Palooskis, Nerkles, even Nerds, and the “bustard, who only eats custard with sauce made of mustard.” But there really are bustards… and now we’ve seen them! The largest species, the kori bustard, could reach the back of an ostrich (and lives in much the same open semi-arid habitat), has a dandy crest, and can fly at the speed of an underpowered combi (VW van) (pers. obs.). We’re not sure if it eats mustard or custard. Some other amazing birds we feel lucky to have seen: hornbills, korhaans (2 species so far, just slightly smaller than bustards, also long-legged desert denizens), vultures, pied (black and white) hawks, and of course flamingos, hundreds of them every day at our study site. Did you know that flamingos have voices similar to geese?
On this trip to the coast, we again took the tar road until the dirt cut-off to Henties Bay that skirts the Spitzkoppe. Two months ago, I wouldn’t have thought it possible that a “desert” landscape could look so lush – it seems to continue to green with summer rains. The “ah-ha” moment was seeing the patches of ground along the road that had appeared as desolate as “war zones” in January: bushes and small trees had been mercilessly uprooted and piled together sort of like slash, leaving just bare dirt behind. But now, these clearings are knee-high in grasses and forbs, gently waving in the wind. There is a sweet smell in the air. And one grass is particularly beautiful, with silvery seed heads nodding.
Even eastern areas of the Namib desert, areas previously seen with tufts of brown grass, now show green. The cows are beginning to lose their angular, ribbed appearance; goats are filling out; and grazing donkeys seem very happy. Just a note about donkeys: It’s taken us a while to realize that donkey carts remain an important means of transportation, particularly in rural areas. Teams of 2, 3, or 4 (sometimes combined with horses) can be seen traveling on dirt roads or along the margins of the tar roads in parallel tracks. Some of the donkeys look a little raw, underfed, and overworked. But they definitely are powered by renewable energy!
Into the western Namib, however, the dominant color is sandy beige-red-brown. Although we have personally witnessed 3 precipitation events on the coast this year, it is still not enough (rain, soil, seed bank?) to make obvious changes. Much of the vegetation consists of sparsely-spaced dark clumps of sand-holding plants. I always initially see these shapes as potential animals! But the animals of the desert look like sand and shimmering heat and are cryptic until startled and in motion.
There has been fantastic weather to observe from afar while camping on the beach near The Salt Company: Semicircular double rainbows, from rain caught by the setting sun. Just past dark, the lightning begins inland, so far away that we rarely hear thunder, sometimes lighting up a sheet of rain, or billowing clouds, or just streaking down to the ground. This is a perfect storm for Katie, who enjoys the fireworks but is troubled by the rumble of thunder.
We had only one uncomfortable night camping this time: the night was still and hot, like a steamer inside the Combi. In the absence of an ocean breeze, flies of all shapes and sizes and speeds gathered on our food and found their way into our sleeping area. When a bit of wind did blow, it was from the east, putting us downwind of the guano platform and directly in the path of the scent of 10s of 1000s of cormorants. We now call this platform the “stinky bird place”, although the proprietor says you get used to it: it’s the scent of money. In the middle of the night, Alan opened the sliding door on the side of the van and spent two hours on the alert, occasionally flashing the headlamp into the eyes of circling hyenas. (Okay, they probably weren’t really circling. That was just for African effect. They were hanging out at the fence line, although we know from their tracks that they do sometimes pass within a few meters of the Combi at night.)
Over the weekend, we did a self-guided tour of all the salt ponds, ranging in salinity from seawater to salt. From those with any life in them, we collected algal and water samples. For those of you with some marine training, we can report finding Dunaliella, ciliates, rotifers, ostracods, Ulva (was Enteromorpha), and a monoseriate, branched green alga, possibly Cladophora. For those of you who read any comics as kids, you’ll be happy to know that we found sea monkeys in the wild: brine shrimp by the millions!
With a month of sampling and thinking about the salt ponds, we finally felt ready to write down observations and questions for the Kleins. That document initiated a 3-hour conversation and confirmed that we can do a variety of experiments in the oyster pond, camp near their hatchery, and use their amazing workshop, which is an enormous room filled with Swedish machinery, much of which was unrecognizable to JR, but AT says they could basically build a motor from scratch in there. We used their drill press to drill tiles and watched them build a clam rake to Alan’s specifications. They do a lot of their own machinery repair, plus make such things as stainless steel nails (the correct 316 type for the guano platform can’t be acquired locally). With access to this workshop and the first “real” hardware store we’ve found, we feel like we’ve almost made up for the absence of Jack’s Country Store at Willapa Bay.
Hooray! We set up our first research project, which will compare growth and resources used by oysters transplanted near the “ocean” and throughout 2 salt ponds. Here, we wonder how much nitrogen in the salt pond comes from birds vs. ocean. This is similar to work in Willapa, except at a much smaller spatial scale (30 ha pond). We epoxied 2 oyster species to 15x15 cm tiles (this size tile is used everywhere in conjunction with concrete for building). To deploy them throughout the pond, we borrowed a “research vessel” – small rowboat (the motorized boat used by the oyster workers seems to have a lawnmower motor attached to a horizontal 1 m rod with a propeller on the end – the propeller is lowered just barely into the shallow water). Alan stood waist-deep in water and calf-deep in anoxic sediment of biodeposits and mica, then used a mallet and steel rod to pound a small hole in the hard gypsum layer. Slip out the rod, slip in a mahogany pole, cable tie the tile to the pole, and one sample is done: we set out about 35. Oysters (Ostrea edulis) spawned on Mar. 7, making a cloud of sperm in the water – just like in all the pictures we’ve seen.
Deploying the tiles took the whole day, so the sun was setting by the time we set up camp, and we ate curry-in-a-bag in the dark. We had a visitor: a gerbil, distinguished by the dark tip to its tail (and the fact that there are no coastal mice). We’d seen lots of tracks, but this was the first individual in the flesh. Common, but interesting daytime visitors are Camponotus ants, about a cm long with 2 bright orange spots on their black velvet abdomen. These apparently can spray formic acid when irritated, so we’ve tried not to irritate them! At least one beetle takes advantage of the ants’ nasty reputation by being the same size and color, complete with 2 bright orange spots to mimic.
On Tuesday, Mar 4 we attended a Namibian Mariculture Association meeting and had a fun time comparing the markets, methods, and magnitudes of oyster culture in Walvis and Willapa Bays. Bottom line: there are really teeny tiny operations here, but they are all looking for access to the high-end oyster market (4-Rand oysters, worth slightly more than 50 cents apiece). No one sells shucked meat; lots sell frozen in the shell (we’re dubious). The Namibian growers have been focusing on selecting fast-growing oysters, so it was good to be able to pass along a broad consensus that selection for survival is much more important. On our way from the meeting in Walvis Bay to our “campsite” in Swakopmund, we saw evidence of a sulfide eruption: tropically-blue water just along the shore. What does this bode for their oysters? Only time will tell.
Week 7 trip to coast
2/16-2/20 2008
On the drive to the coast by tar road, we again saw hundreds of wheeling kites – our bird book says this is a typical response to termite emergence. The kites appeared to be catching termites in their claws – each would periodically swing its legs forward and its head down, as if picking something off the talons. The talons certainly are not built for catching termites. We saw them up close because Alan picked up a stunned (and probably mortally wounded) bird that had been hit by a truck. The feet and claws reached well around his finger, with each talon more than a cm long and deadly pointed.
We exited the tar road to take the dirt “cut-off” to Henties Bay and stopped to campe at the community campsite at Spitzkoppe. Exactly our style. Very rustic campsites, spaced hundreds of m apart, nestled in spectacular rock formations. Up close, the Spitzkoppe rocks are conglomerates of small, rough pebbles, great for grip when you’re climbing upslope. Even Katie enjoyed the rock-climbing experience (and we saw no snakes, even though the adults fretted about them). We arrived just after a rain, and the air smelled of bay spice and moisture, birds were singing, and rock hyraxes – hundreds of them – whistled from caves and ledges. We fortuitously camped near an area with rock paintings – a lion, rhinoceros, and people were easily recognizable, but the technique of achieving red images on the rock face unclear. The most unexpected aspect of the camp was that “community” means it is indeed run by local people, rather than as a resort of relic colonialism. We stopped en route at one of the roadside stands where we selected a piece of aquamarine with black tourmaline to send to a rock-loving friend in the US. (Other options: garnet, sodalite, quartz, many more…) The stand included two additional pieces of architecture: a m-high hut made of branches angled to a point and daubed in manure (we assume, since sand clearly wouldn’t hold together, and clay is not available); and a slightly taller square cube with walls of soda and beer cans, strung in vertical columns.
On this trip, we went to the salt ponds on 2 days with Hilma and Magdalena (faculty and student at Poly, respectively), caught fish (tilapia, mullet), and discussed salt pond food webs and oyster production. Along the margins of the oyster pond, clams were gaping and dying – these are Manila clams introduced from Europe (but originally from Asia), also familiar to us because they are introduced in Washington. These clams bear some further study: their presence all around the pond indicates at least one successful recruitment event, but the strange size structure (no small clams) means that recruitment may not happen regularly. We suspect the clams were dying from unusually high temperatures and other stresses that contribute to “summer mortality”.
The trip was short because it was bookended by strategic planning meetings in Windhoek...
Week 6 trip to coast
2/11-2/14 2008
On this trip, we took a new road to the coast. On the map, it is labeled C26, but widely known as the Khomas-Hochland road. The “C” part means it is not paved (B is for tar-road). Half of the drive – by distance, and by far the majority by time – was through mountainous territory with sinuous roads, rather washboard, and periodically cut through by intermittent rivers. We drove much of it at 30 kph. Cattle and horses along the way indicate that the area is grazed, although the soil is so thin that rocks show through everywhere, in lines suggesting sedimentary layers turned on end. It was a fantastic drive for charismatic megafauna: when we stopped to look at a few oryx (whose dramatic coloring makes them stand out), we also startled a dozen kudu, totally invisible in their lightly banded brown coats until they moved. Charismatic birds included some really large and pied (black and white) ones – we’re marking dates and places in our bird book when we can identify species, and we added more than a half dozen on this trip.
The road emerges from the mountains almost directly into Namib-Naukluft park, where oryx, springbok, ostriches and zebras congregated in remarkable numbers on the eastern edge, which was beginning to green from recent rain. We saw Welwitschia mirabilis for the first time in the wild, looking just as scraggly and other-worldly as in the UW greenhouse. Apparently, its two leaves can grow for a millennium.
We camped for 3 nights around The Salt Company, making forays there each day to begin understanding how the water moves among the ponds and which species are present. We were surprised that the inlet canal, where seawater is first pumped, had no clams, mussels, or barnacles – we wondered if the pump was fatal to larvae, or if the flamingos were dancing them to death, but then learned that the canal periodically dries out when the pump is turned off. In any case, many species that appear not to be present in the inlet to the oyster salt pond, suddenly appear in the pond: barnacles on the rocks and floats, a reddish bryozoan, isopods in the Gracilaria, under rocks, and sometimes just swimming openly. We tentatively identified the isopods as Paridotea fucicola [later: nope – the uropod ramus dimensions became clearer with a better ‘scope], but it wasn’t easy without a dissecting kit or dissecting microscope: I had to pull out the mouthparts and uropods by hand and try to look at them under the compound ‘scope that Mr Klein uses to observe oyster larvae.
Our camping trip was a bit of a shake-down: we spent the first night at a commercial campground, which is good since the propane canisters recommended for our Bleuet stove didn’t actually fit, and we used the kitchen stoves available at the campground instead. On our second night, we opened cans of mutton and TVP curry with a knife (stainless steel beats aluminum) because our mess kit includes a cork/bottle opener but no can opener. By the third night, we felt that we were settling into more of a routine. All 3 of us pack into the back of the Combi to sleep even though it’s 4” too short for Alan (he gets the spot where one of the seat backs folds down.
During our stay, the winds began blowing from the SW for the first time in weeks: if this holds, upwelling should resume and the water temperatures cool and become less stressful for aquaculture.
On this trip, we took a new road to the coast. On the map, it is labeled C26, but widely known as the Khomas-Hochland road. The “C” part means it is not paved (B is for tar-road). Half of the drive – by distance, and by far the majority by time – was through mountainous territory with sinuous roads, rather washboard, and periodically cut through by intermittent rivers. We drove much of it at 30 kph. Cattle and horses along the way indicate that the area is grazed, although the soil is so thin that rocks show through everywhere, in lines suggesting sedimentary layers turned on end. It was a fantastic drive for charismatic megafauna: when we stopped to look at a few oryx (whose dramatic coloring makes them stand out), we also startled a dozen kudu, totally invisible in their lightly banded brown coats until they moved. Charismatic birds included some really large and pied (black and white) ones – we’re marking dates and places in our bird book when we can identify species, and we added more than a half dozen on this trip.
The road emerges from the mountains almost directly into Namib-Naukluft park, where oryx, springbok, ostriches and zebras congregated in remarkable numbers on the eastern edge, which was beginning to green from recent rain. We saw Welwitschia mirabilis for the first time in the wild, looking just as scraggly and other-worldly as in the UW greenhouse. Apparently, its two leaves can grow for a millennium.
We camped for 3 nights around The Salt Company, making forays there each day to begin understanding how the water moves among the ponds and which species are present. We were surprised that the inlet canal, where seawater is first pumped, had no clams, mussels, or barnacles – we wondered if the pump was fatal to larvae, or if the flamingos were dancing them to death, but then learned that the canal periodically dries out when the pump is turned off. In any case, many species that appear not to be present in the inlet to the oyster salt pond, suddenly appear in the pond: barnacles on the rocks and floats, a reddish bryozoan, isopods in the Gracilaria, under rocks, and sometimes just swimming openly. We tentatively identified the isopods as Paridotea fucicola [later: nope – the uropod ramus dimensions became clearer with a better ‘scope], but it wasn’t easy without a dissecting kit or dissecting microscope: I had to pull out the mouthparts and uropods by hand and try to look at them under the compound ‘scope that Mr Klein uses to observe oyster larvae.
Our camping trip was a bit of a shake-down: we spent the first night at a commercial campground, which is good since the propane canisters recommended for our Bleuet stove didn’t actually fit, and we used the kitchen stoves available at the campground instead. On our second night, we opened cans of mutton and TVP curry with a knife (stainless steel beats aluminum) because our mess kit includes a cork/bottle opener but no can opener. By the third night, we felt that we were settling into more of a routine. All 3 of us pack into the back of the Combi to sleep even though it’s 4” too short for Alan (he gets the spot where one of the seat backs folds down.
During our stay, the winds began blowing from the SW for the first time in weeks: if this holds, upwelling should resume and the water temperatures cool and become less stressful for aquaculture.
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